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1.
江淮地区玉米涝渍指标构建及时空特征分析   总被引:1,自引:0,他引:1  
[目的]江淮地区玉米涝渍灾害严重,研究揭示区域玉米涝渍灾害时空发生规律对科学开展区域防洪减灾具有重要意义。[方法]利用1981—2010年江淮地区18个站点地面气象观测数据和农业气象资料,基于作物水分盈余指数(CWSI),引入播种前底墒,根据玉米各生育阶段涝渍敏感性差异,采用层次分析法确定阶段涝渍灾害影响权重,构建适用于江淮地区玉米涝渍等级评估的玉米综合水分盈余指数(CWSIM),并根据典型涝渍年综合指数同对应减产率的线性回归方程,划分春、夏玉米不同等级涝渍的指标阈值。[结果](1)春玉米的轻、中、重涝指标阈值依次为: 080≤CWSIM<101,101≤CWSIM<123,CWSIM≥123; 夏玉米为: 109≤CWSIM<144,144≤CWSIM<179,CWSIM≥179。(2)各阶段水分盈余指数(WSIM)分布规律,春玉米为:出苗—拔节期、拔节—吐丝期呈由北向南的纬向增加分布; 吐丝—成熟期高值区位于安徽省西南临江一带、江苏省淮安市东部、扬州市及其周边区域,低值区位于安徽省北部及中部的中心区域、江苏省东南边缘,其余为中值区。夏玉米为:出苗—拔节期呈由北向南的纬向增加分布; 拔节—吐丝期高值区位于江苏省东北部,低值区位于安徽省中部及临江一带,其余为中值区; 吐丝—成熟期指数呈由西向东的经向增加分布。(3)江淮地区近30年,春玉米CWSIM值由北向南呈纬向增加分布。整体指数在不同时期的排序为1991—2000年>1981—1990年>2001—2010年; 夏玉米CWSIM值由北向南呈近辐射状条带增加分布,不同时期指数排序为1991—2000年>2001—2010年>1981—1990年。[结论]安徽省沿江一带是玉米涝渍害发生的重灾区,且1991—2000年较其前后10年涝情最重。  相似文献   

2.
[目的]根据区域景观差异性进行土地利用景观分区,以期为土地利用分区和土地利用政策制定提供理论依据。[方法]文章以重庆市永川区为研究对象,以2005年和2015年的遥感影像为基础数据源,借助RS和GIS技术对2期的影像进行解译,得到永川区2期土地利用类型图; 利用景观指数法与Shannon 多样性t值检验法进行全区土地利用景观格局变化的数量结构和各乡镇土地利用景观变化显著性分区研究。[结果](1)从类别层级分析, 2005—2015年间,建设用地、林地表现为增加趋势,耕地、草地、未利用地表现为减小趋势。耕地为永川区的优势景观类型(2005年和2015年各占土地总面积5446%、4976%),耕地、建设用地、林地受人为干扰强烈且趋于规则化。(2)从景观层级分析,蔓延度指数增大,Shannon多样性指数、Shannon均匀度指数、散布与并列指数、景观形状指数均减小。(3)利用Shannon多样性t检验法对永川区进行土地利用景观格局分区。景观变化极显著区,主要位于主城区及其周围地区,城市化现象显著,人为活动影响大; 景观变化显著区,该区土地利用程度较弱, 2005—2015年林地和水域面积增大,耕地面积减小; 景观变化不明显区,该区主要分布在远离中心城区,经济欠发达,景观格局变化不明显,人为活动干扰不明显。[结论]永川区各乡镇的土地利用景观格局变化差异性,表明在自然因素稳定的条件下,今后应因地制宜地加强人为因素的调控,保证各乡镇土地利用景观格局稳定协调发展。  相似文献   

3.
1960—2015年呼伦贝尔草原气温和降水格局变化特征   总被引:1,自引:0,他引:1  
[目的]利用1960—2015年呼伦贝尔草原区逐日气象数据,分析了该地区这56年来气温和降水的分布与变化规律。[方法]文章采用Mann Kendall非参数趋势检验和Sen′s斜率估计分析了温度、降水变化的趋势和变化速度。[结果](1)呼伦贝尔草原区过去56年中气温呈现出极显著波动增加的趋势,其中第二季度增温的趋势最明显,年均温增加中值005℃。海拉尔区增温速度为草原区最快,年增加中值004℃。(2)呼伦贝尔草原区这56年中降水呈现出不显著的波动下降趋势,年降水减少中值041mm。其中第三季度降水量显著减少,年降水减少中值092mm,第一、四季度降水量显著增加,年降水增加中值007~023mm。第二季度变化较小。满洲里市降水量极显著下降,下降速度为草原区最高,年降水减少中值125mm。(3)1~5mm降水次数和总降水贡献呈显著增加趋势,年增加中值0102%, 5~30mm降水次数和降水贡献呈现减少趋势,单次降水30mm以上频率很低。(4)历时1~2d的降水是研究区最主要的连续降水类型,独立单日降水呈现不显著增加趋势, 2~3d连续降水呈现不显著减少趋势,连续4d和4d以上降水事件较为罕见。[结论]呼伦贝尔草原区过去56年整体看呈现出暖干化的趋势,年内尺度看降水呈现均匀化趋势,第三季度减少,第一、四季度增加。降水格局表现为分散化趋势,极端降水事件减少,小雨增加; 连续降水减少,单日独立降水增加。  相似文献   

4.
[目的]文章研究2007—2016年10年山东德州的耕作层平均地温的变化趋势和近50年来的气候突变情况。[方法]根据2007—2016年山东德州地区10个县、市、区,1967—2016年德州市德城区夏玉米生长季(6—9月)耕作层5cm、10cm、15cm、20cm平均地温,及同期月平均气温资料,采用气候倾向率、累积距平、信噪比等气候诊断方法。[结果](1)近10年德州地区各县市夏玉米生长季耕作层平均地温、各月平均地温大部分呈上升趋势,临邑、夏津两县各土层均呈下降趋势。各层上升幅度最大值均出现在齐河,为233~280℃/10年。(2)同时段的地温高于气温,地气温差均为正值,5~20cm温差范围分别为11~20℃、10~17℃、08~15℃、06~13℃,各层地气温差最大的是庆云、宁津,最小的是武城。浅层地温与气温的变化存在明显的正相关关系。(3)近50年来,各月平均地温都出现了一次显著的波动。6月份5cm、10cm平均地温在2004年发生了气候突变,7月份10cm平均地温在2005年发生了气候突变,8月份5cm至20cm平均地温在1981年均发生了气候突变。[结论]以上各月浅层地温气候突变前为相对偏冷期,突变后为相对偏暖期。该地区夏玉米生长季期间耕作层地温的上升,有利于夏玉米根系生长和充分吸收深层养分、水分,增加玉米干物质积累,有利于夏玉米提高产量,降低生长季后期其他气象因素带来的不利影响。  相似文献   

5.
[目的]探讨区域土地利用结构的时空变化,为政府制定土地利用规划提供参考。[方法]基于信息熵的基本原理,利用2002—2014年长株潭地区各县(市、区)土地利用变更数据和相关社会经济资料,对研究区域土地利用结构的时间变化规律和空间分异特征进行了分析,并运用灰色模型进行了预测分析。[结果](1)从整体上看,耕地、园地、林地、草地、水域及水利设施用地、其他土地所占比例呈递减趋势,城镇村及工矿用地、交通运输用地所占比例呈递增趋势。(2)土地利用结构信息熵在2002—2014年期间总体呈先下降后上升的变化趋势,从2002年的1350 3 Nat上升到了2014年的1362 3 Nat。(3)各县(市、区)土地利用结构的信息熵呈现出较大的时空差异。(4)运用灰色模型预测可知,到2026年土地利用结构信息熵出现上升趋势。[结论]当地政府必须高度重视,大力提高土地资源配置效率与集约利用水平,优化城市土地利用结构,合理布局城市用地,实现土地资源的可持续利用。  相似文献   

6.
[目的]探究在制度改革背景下的农业生产力发展水平和地区差异,有利于全面了解农业发展状况,为后期农业政策的制定、调整以及农业发展提供理论基础。[方法]文章利用DEA-Malmquist指数法对我国西南地区5个省(市)农业全要素生产率(TFP)水平变化发展趋势进行分析,并在此基础上对不同地区农业TFP差异变化和发展趋势进行预测。[结果](1)Malmquist指数分析结果表明,我国西南地区农业TFP呈缓慢增长的趋势。通过对不同地区农业TFP结果进行比较,四川省农业TFP有先逐渐上升后下降的趋势,而技术进步是影响四川省农业TFP增长的原因;(2)重庆市农业TFP也是呈现波动式缓慢增加的趋势,年平均增长率为354%; 贵州省农业TFP近20年来增长速度最快,主要影响因素为技术进步; 云南和广西农业TFP也均呈缓慢增长的趋势,技术效率和技术进步在不同时期对农业TFP的影响有所差异。(3)收敛性分析结果表明,我国西南地区农业TFP差异有减小的趋势,并且不同地区农业TFP水平具有向各自稳定状态发展的可能性。[结论]我国西南地区农业TFP增长与技术进步具有较高的同步性,因此,制约我国西南地区农业全要素生产率增长的关键因素是农业科技进步。在供给侧结构性改革背景下,必须以市场需求为科研导向,加大科技创新投入力度,促进我国西南地区农业的可持续发展。  相似文献   

7.
[目的]文章旨在分析乡村旅游生态化对新型城镇化建设的影响。[方法]运用综合指数法建立新型城镇化评价体系,分析2000—2016年浙江省新型城镇化程度,进而利用数理统计模型分析乡村旅游生态化对新型城镇化的影响。[结果]浙江省新型城镇化发展主要包括2000—2005年新型城镇化初始阶段,城镇化发展水平受基础设施等条件限制呈波动上升趋势,以及2006—2016年,属于新型城镇化快速发展阶段,政府对于新型城镇化的高度重视使城镇化指数由0436上升至0869,年均增长率高达0093。乡村旅游生态化对新型城镇化的影响主要包括3个方面:(1)在人均家庭经营农家乐收入比方面,其对浙江省新型城镇化建设的直接效应为正,间接效应为负; (2)在森林覆盖率方面,其对浙江省新型城镇化建设的效应为正,直接效应系数为0098,间接效应指数为0074,影响相对较大; (3)果园面积方面,其对浙江省新型城镇化建设的影响不大,但直接效应和间接效应均为正。[结论]乡村旅游的生态化对新型城镇化具有一定影响,且正向影响远大于负向影响。  相似文献   

8.
[目的]活动积温是农业气候资源评价最重要、最普遍的指标之一。利用1960—2009年河南省17个气象站点的逐日均温数据,研究1960—2009年河南省≥0℃和≥10℃活动积温时空变化。[方法]运用5日滑动平均法计算≥0℃和≥10℃积温; 基于GIS平台进行空间插值,点面结合地研究了两种活动积温的时空变化特征。[结果](1)总体变化格局上,1960—2009年河南省≥0℃和≥10℃积温都呈上升趋势,前者年均值5 226℃、增加013%/年、振荡周期4年,后者年均4 6585℃、增加022%/年、振荡周期3年; (2)代际变化上,≥0℃和≥10℃积温变化趋势相似,均以2000年为界,之前基本没有明显变化,而之后则发生较显著增加趋势,均呈自南而北的增大态势; (3)在空间格局上,虽然两种活动积温都展示着西低东高、北低南高的趋向,但≥10℃积温的趋势更加明显; (4)两种活动积温的代际数值均与纬度和海拔呈显著负相关。[结论]河南省活动积温的区域分异特征与其他地区相比存在明显差异,但其活动积温代际变化区域特征与其他省区相比存在相似之处。  相似文献   

9.
[目的]东北三省是我国大豆生产的重要基地,也是国家种植结构调整的重点区域。研究分析了1980—2010年东北三省大豆时空演变特征,为合理制定种植结构调整政策、加快推进农业供给侧结构性改革提供科学的空间信息参考。[方法]综合卫星遥感技术和空间信息重构模型优势,基于交叉信息熵方法,构建了作物空间信息重构模型SPAM China,对1980—2010年东北三省大豆种植空间分布、时空演变、重心迁移等进行了研究。[结果]1980—2010年东北三省大豆种植区域小幅增加,大豆种植面积栅格数量从6 703个增加至7 214个,松嫩平原、三江平原以及吉林省中部地区是东北三省的大豆主产区; 种植面积大幅增加,单位栅格面积增加1 000hm2以上的栅格数量增加明显,面积增加区域主要位于北纬47°~50°之间和东经1255°~131°之间; 东北三省大豆种植面积重心分别向东迁移10620km,向北迁移20857km,辽宁省、吉林省大豆种植面积重心南移,黑龙江省基本保持不变。[结论]1980—2010年东北三省大豆种植面积空间分布小幅增加,但时空变化特征显著,种植面积重心向北向东迁移。  相似文献   

10.
[目的]通过选取相关的指标因子,针对耕地生态环境,从压力、状态、响应3个层面构建耕地生态环境承载力评价体系,并从数量、空间分布两方面对评价结果进行分析,以增强评价结果的应用性与针对性。[方法]从压力—状态—响应3个方面选取评价指标,选取14个指标因子,分析河南省不同区域耕地生态环境承载力的影响。[结果]从数量分布方面看,河南省耕地生态环境承载力以一般区为主,占比达到4154%,承载力良好区最少,占比1193%。空间分布上,河南省耕地生态环境承载力表现出明显的地域差异性,呈现出由周围地区向中部地区逐渐减弱的趋势。三门峡市、商丘市等处于耕地生态承载力的第I等级; 郑州市、开封市等处于第Ⅳ等级。[结论]虽然文章针对耕地生态环境承载力研究还处于探索阶段,但结果可为河南省耕地生态环境的管理与监测提供依据,并服务于其资源利用与区域发展方针政策的制定。  相似文献   

11.
The theory of demand and supply implies a positive relationship, or “price transmission” between the prices of products at different stages of manufacturing. This relationship was investigated with quarterly prices of softwood stumpage in the US South, and national prices of forest products, from 1977 to 2002. All prices, net of inflation, were found to be nonstationary and there was no evidence of co-integration between prices. Vector autogressive models, augmented by Granger causality tests and multiplier analysis showed that there was a one-to-one permanent positive response of the southern sawtimber stumpage price to a permanent change in the national lumber price. There was also a one-third permanent positive response of the national paper price to a permanent change in the national pulp price. There was no relation between regional pulpwood prices and national pulp or paper prices. When price transmission was significant, the full adjustment took about 2 years.  相似文献   

12.
Owners, local residents, government, and conservation organisations can express divergent preferences in the development and management of local woodlands. The perceptions of these four groups were examined, in the context of three community woodlands in Eastern England, using an ecosystem function framework. In a pilot study, residents were able to allocate a relative importance to woodland ecosystem services which were then related to “regulation”, “habitat”, and “production” or “information” functions. However residents also placed importance on negative services or “dis-services” associated with the woodland ecosystem. Therefore a fifth category of “dis-services” was included in the main survey which included 84 local residents, three woodland owners, three government institutions, and six representatives from conservation groups. Each of the four groups placed greatest importance on services associated with habitat (16–39% of the total importance) and information (30–50%) functions suggesting, in this example, mutual interest in the use of woodlands as a habitat or recreational resource. By contrast a potential area of difference was the particularly high importance placed by one owner on dis-services such as fly tipping. In addition the woodland owners placed higher importance (10–20%), than local residents and conservation groups (7–9%), on the productive services of the wood. This suggests a need for communication when production-related operations affect recreation. The ecosystem function framework appears to be a useful approach for highlighting potential tensions and areas of mutual interest in the management of semi-natural ecosystems.  相似文献   

13.
China is one of the largest wine importing countries in the world and is poised for continued import growth in the future. Increased wine purchases throughout China have given rise to persistent fraud where fake wines are packaged and sold with counterfeit contents and labels. For exporting countries like France, counterfeit wines displace market share, damage foreign brand reputation, and cause distrust in consumers who are aware of counterfeiting problems throughout the country. We examine the impact of fraudulent wine events (as measured by negative media reports) on Chinese wine demand differentiated by supplying country. We employ the Rotterdam demand system and a switching regression procedure to estimate import demand and compare results across different media variable specifications. Results consistently show that negative reports disproportionately affect French wine regardless of how the media variable is specified. This is not surprising because most fraudulent events involve French wine counterfeits.  相似文献   

14.
In recent years earthquakes and their secondary hazards have claimed the largest number of lives of all large natural disasters. Some of the world’s most earthquake-prone zones are also areas of high population density. The impact is magnified by vulnerability factors including non-enforcement of building codes, knowledge gaps, urban poverty and poor governance capacity to manage and reduce earthquake risks. Poor security of land tenure and property rights increases the vulnerability of people and affects their ability to respond to natural disasters.Earthquake recovery and reconstruction provides very significant challenges for land agencies, with these challenges differing from one country to the next due to differences in the local context. Drawing on contrasting case studies in Haiti, Nepal and New Zealand this paper identifies the common post-earthquake land administration functions and challenges that may apply to many contexts. These lessons provide land agencies and other key stakeholders with a summary of the challenges an earthquake poses for land administration at different post-disaster stages. We also discuss the policy and regulatory, institutional, operational and preparedness lessons for land administration. From these lessons we propose a framework for evaluating the earthquake-responsiveness of a land administration system. This framework can be used by a land agency in an earthquake prone region, or where an earthquake has recently occurred, to assess what challenges to land administration might occur in the event of an earthquake, and the preparedness of their land administration system.  相似文献   

15.
This paper analyses poverty and calorific undernourishment in the Indian state of Gujarat, where high and market‐led industrial growth has resulted in rapid economic improvement. The study is carried out through a combination of secondary and survey‐based data. We conclude that the neoliberal agenda of uncontrolled, outward‐looking growth has not resulted in significant reduction of poverty or malnourishment in rural areas. Furthermore, while land ownership is officially used as a proxy for wealth distribution, class position appears a better predictor of poverty status in the rural areas than landownership per se. At the policy level, there is a need to revive the agrarian economy and create new non‐agricultural assets, and the primary focus in the state must shift to the distribution of created assets rather than a single‐minded focus on growth.  相似文献   

16.
This paper tests the ‘systems of innovation’ hypothesis for a selection of crops in Ghana and Burkina Faso that have shown significant growth in production over an approximately 20-year period. The question is whether such growth can only occur if supported by a system of innovation. Using two indicators (a common understanding on objectives and priorities, and a high level of interactivity), we find little evidence for the existence of anything that might be considered a high functioning system of innovation.  相似文献   

17.
The values ascribed to industrial tree plantations are often controversial. Hence knowledge of their perceived impacts is important for improving their integration in rural landscapes. In 2016 we conducted household surveys with 606 respondents living in villages adjacent to acacia, teak and pine plantations across three islands in Indonesia (Java, Borneo, Sumatra). Results show that perceptions toward pine and teak plantations tend to differ from those toward acacia pulpwood plantations in several ways. Pine and teak plantations are perceived to have a higher number and variety of benefits and services, a higher number of positive impacts, a better environmental record, and to present more opportunities to local people for use of plantation land and products for improving rural livelihoods. In addition, we find that villagers around acacia pulpwood plantations tend to seek economic development and infrastructure to open up remote areas, yet their expectations were often only partially met. Recommendations from our analysis include: the role of the State in plantations must be clarified and potentially reinforced; the role of institutions as intermediaries is fundamental; and contributions by communities to design of management plans should be accommodated.  相似文献   

18.
Large‐scale tree plantations in high rainfall upstream areas can reduce fresh water inflows to river systems, thereby imposing external costs on downstream irrigation, stock and domestic water users and wetland interests. We take the novel approach of expressing all benefits and costs of establishing plantations in terms of $ per gigalitre (GL) of water removed annually from river flows, setting upstream demands on the same basis as downstream demands. For the Macquarie Valley, a New South Wales sub‐catchment of Australia’s Murray‐Darling Basin, we project changes in land and water use and changes in economic surpluses under two policy settings: without and with a policy requiring permanent water entitlements to be purchased from downstream parties, before plantation establishment. Without the policy, and given a high stumpage value for trees ($70/m3), upstream gains in economic surplus projected from expanding plantations are $639 million; balanced against $233 million in economic losses by downstream irrigators and stock and domestic water users for a net gain of $406 million, but 345 GL lower mean annual environmental flows. With the policy, smaller gains in upstream economic surplus from trees ($192 million), added to net downstream gains ($138 million) from sale of water, result in gains of $330 million with no reduction in environmental flows. Sustaining the 345 GL flow for a $76 million (406–330) reduction in gains to economic surplus may be seen to cost only $0.22 million/GL; but this is much lower than the market value of the first units of that water to agriculture and forestry.  相似文献   

19.
Fieldwork shows that many Sierra Leonean producers do not receive the official producer price for their coffee and cocoa, due to the concentration of buying stations, credit relations, the small quantities offered for sale, and the lack of marketing knowledge of the numerous and unorganized farmers. To the traders underpayment may seem economically justifiable to a certain extent, but to the farmers it means poverty and debt. A new village marketing centre project aims at remedying this situation and has already led to higher prices. Although no longer allowed to take their "just" share from the producers, traders are still willing to deal with the new centres.  相似文献   

20.
The cost of accessing healthcare can be a major determinant of disease prevalence, which in turn has short‐ and long‐term welfare implications on poor households. In response, governments in developing countries often resort to subsidizing the cost of drugs, which, while perhaps easier to administer, may not always be the most effective way of addressing healthcare cost. In this regard, we analyze the impact of different types of household level health expenses on disease incidence and agricultural production efficiency. We use data from the 2006 Uganda National Household Survey, which covered approximately 7,400 households. The results suggest that a 10% increase in consultation, medicine, and hospitalization expenses would reduce malaria incidence respectively by 35.6%, 20.5%, and 21.3 %, which translates into a 1.1%, 0.6%, and 0.6 % decrease in agricultural inefficiency, respectively. The results indicate that helping poor households meet expenses for consultation through subsidies or eliminating consultation fees has a larger impact on malaria incidence and agricultural productivity among poor rural households than subsidizing the cost of medical drugs, the most common avenue chosen by developing country governments in the fight against the disease.  相似文献   

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